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FTX Series

High Force Electric Actuator

Industrial - Exlar

Benefits:
  • Easily retrofit into existing equipment. 
  • Increased motion control compared to fluid actuation. 
  • Lower total cost of ownership. 
  • Easy integration with 3rd party motors and gearboxes. 

Features:
  • Long, robust actuator life due to Exlar roller screw technology. 
  • Sealed to IP65S for harsh industrial environments. 
  • Ideal hydraulic cylinder replacement. 
  • Minimal maintenance. 
  • Flexible mounting options. 
  • Stroke lengths up to 48” (1200 mm). 
More Details

Overview

FTX Series

Quick Data
ModelFrame Size mm (in)Strokes mm (in)Max Continuous Force kN (lbf)Max Speed mm/s (in/s)
FTX09595 (3.7)
150 (6), 300 (12), 600 (24), 900 (36), 1200 (48)
22 (5,000)
1,500 (59.3)
FTX125125 (5.0)
150 (6), 300 (12), 600 (24), 900 (36), 1200 (48)
44 (10,000)
583 (23.0)
FTX160160 (6.3)
150 (6), 300 (12), 600 (24), 900 (36), 1200 (48)
89 (20,000)
1,000 (39.0)
FTX215215 (8.5)
150 (6), 300 (12), 600 (24), 900 (36), 1200 (48)
178 (40,000)
875 (34.0)

HYDRAULIC CYLINDER REPLACEMENT

Hydraulic cylinders provide long life and high force in a small package size. The FTX Series high force electric actuators were designed specifically to allow migration from traditional hydraulic actuation to electric. Based on planetary roller screw technology, the FTX offers life and force density not attainable with more common ball screw based electric actuators. With up to 15X the life and 2X the force density, the roller screw based FTX is the right choice when migrating from hydraulic to electric actuation.


High Speed Electric Actuator Benefits

Rugged and Reliable

Hydraulic cylinders are commonly installed in harsh industrial settings. Therefore all FTX Series models are environmentally sealed to IP65. In addition, its planetary roller screw mechanism withstands significantly higher shock loads than weaker ball screw alternatives. Migrate to electric with confidence knowing the FTX Series is every bit as rugged and reliable as the hydraulics they are designed to replace.

Minimal Maintenance

More and more machine builders are looking to eliminate the mess and downtime associated with hydraulic fluid leaks. Electric actuation not only eliminates the problems associated with fluid leaks, it offers significantly higher levels of performance and flexibility than is possible even with servo-hydraulic solutions. FTX Series roller screw actuators allow machine builders to meet the ever-increasing performance demands of their customers while minimizing or eliminating the maintenance issues associated with traditional hydraulic solutions.

Related Industries

                 


                  


Quick Data
Models:FTX095, FTX125, FTX160, FTX215
Frame Sizes:95 mm (3.74 in), 125 mm (5 in), 160 mm (6.3 in) 215 mm (8.5 in)
Screw Leads – mm (in)5 (.20), 6 (.25), 10 (.39), 12 (.50), 20 (.79), 30, (1.18)
Stroke Lengths:150, 300, 600, 900, 1200 mm (5.9, 11.8, 23.6, 35.4, 48 in )
Linear Speed:up to 1500 mm/s (59 in/s)
Maximum Force:up to 178 kN (40,000 lbf)
Standards/Ratings:IP65S
 

AAA = Frame Size
095 = 95 mm
125 = 125 mm
160 = 160 mm
215 = 215 mm

BBBB = Stroke Length
0150 =   150 mm
0300 =   300 mm
0600 =   600 mm
0900 =   900 mm
1200 = 1200 mm

CC = Screw Lead
05 = 5 mm (FTX095, FTX125)
06 = 6 mm (FTX160, FTX215)
10 = 10 mm (FTX095, FTX125)
12 = 12 mm (FTX160, FTX215)
20 = 20 mm (FTX095)
30 = 30 mm (FTX160, FTX215)

D = Lubrication Type
1 = Grease
2 = Oil
3 = Low Temperature Grease (to -40º C)

E = Rod End Thread 
A = Male, Metric
B = Female, Metric
M = Male, English3
F = Female, English3

FFF = Motor Mounting Configurations1
NMT = None, base unit only
N10 = Inline, includes shaft coupling
P10 = Parallel, 1:1 belt reduction
P20 = Parallel, 2:1 belt reduction

GG = Motor/Gearbox Flange Code
See catalog or motor decoder for details
 
HH = Motor Shaft Code
See catalog or motor decoder for details

III = Shaft Length 
See catalog or motor decoder for details

M = Mounting Options 
N = None
1 = Front Flange, Metric
5 = Rear Clevis, Metric2
7 = Rear Eye, Metric2
9 = Rear Trunnion, Metric
F = Front Flange, English3
C = Rear Clevis, English3 (Not available on FTX215)
G = Rear Clevis, Metric3 (Not available on FTX125 or FTX215)

N = Other Options 
N = None
L =  Limit Switches*


*Ordered Separately


NOTES:
1. Always discuss your motor selection with your local sales representative.
2. Not available with inline or NMT motor mount, contact your local sales representative.
3. Available option. May add lead time

* Some options are not available with every configuration. For options or specials not listed above contact your local representative.

Adjustable External Travel Switche(s)
External travel switches indicate travel to the controller and are adjustable for either the home or end position.

Front Mounting Flange
Front mounting flange, includes thru-holes for face-mounting

Rear Clevis, Metric
Rear clevis mount, allows actuator to pivot while in motion

Rear Eye Mount
Rear eye mount, allows actuator to pivot while in motion

Rear Trunnion Mount
A rear trunnion is a cylindrical protrusion used as a mounting or pivoting point.

Grease
FTX Series actuators are shipped from the factory fully lubricated with high temperature grease. Exlar uses Mobilith SHC 220, a high performance, extreme-pressure grease.

Low Temperature Grease
For low temperature applications, the FTX Series uses Mobilgrease 28. This grease is suitable for actuator applications in ambient temperature ranges from -40°C to 85°C.

Oil
The FTX Series use Mobil SHC 626 for oil fill. The actuator is shipped empty and only receives a light oil coating from the factory for initial test. 

Product Specifications

FTX095 Performance SpecificationsOpen arrow

FTX095 Specifications

    5 10 20
Screw Lead mm 5 10 20
  in 0.197 0.394 0.787
Maximum Force* kN 22.2 22.2 22.2
  lbf 5,000 5,000 5,000
Life at Maximum Force km 392 626 1440
  in x 10^6 15.4 24.6 56.7
C_a (Dynamic Load Rating) kN 95.2 88.3 92.5
  lbf 21,400 19,850 20,800
Maximum Input Torque Nm 22.1 44.3 88.5
  lbf-in 196 392 783
Max Rated RPM @ Input Shaft RPM 4,500 4,500 4,500
Maximum Linear Speed @ Maximum Rated RPM mm/sec 373 750 1,500
  in/sec 14.7 29.5 59.3
Friction Torque Nm 1.12 1.12 1.12
  lbf-in 10 10 10

Intermediate and custom stroke lengths are also available. Belt and pulley inertia varies with ratio and motor selection. Please contact your local sales representative. 
* Maximum allowable actuator-generated force that can be applied routinely. Exceeding this force may result in permanent damage to the actuator. For high force, short stroke applications, consult factory.



FTX095 Weights

  kg lb
Base Actuator Weight (Zero Stroke) 10 21
Actuator Weight Adder (Per 25 mm of stroke) 0.39 0.87
Adder for Inline (excluding motor) 2.9 6.5
Adder for Parallel Drive (excluding motor) 13.1 28.9
Adder for Front Flange 1.9 4.2
Adder for Rear Clevis 5.3 11.7
Adder for Rear Eye 5.1 11.3
Adder for Rear Trunnion 1.9 4.3



FTX095 Inertias

Base Unit Inertia Zero Stroke [kg-m^2 (lbf-in-sec^2)] Add per 25 mm [kg-m^2 (lbf-in-sec^2)]  
—5 mm Lead 8.27 x 10^-4 (7.32 x 10^-3) 2.19 x 10^-6 (1.94 x 10^-5)  
—10 mm Lead 8.33 x 10^-4 (7.37 x 10^-3) 2.42 x 10^-6 (2.14 x 10^-5)  
—20 mm Lead 8.57 x 10^-4 (7.58 x 10^-3) 3.31 x 10^-6 (2.93 x 10^-5)  
       
Inline Drive Inertia Inline Unit - w/Motor Coupling Inline Unit - w/Motor Coupling For Gearbox Mount Add per 25 mm
—5 mm Lead 9.27 x 10^-4 (8.20 x 10^-3) 1.09 x 10^-3 (9.62 x 10^-3) 2.19 x 10^-6 (1.94 x 10^-5)
—10 mm Lead 9.33 x 10^-4 (8.26 X 10^-3) 1.09 x 10^-3 (9.67 x 10^-3) 2.42 x 10^-6 (2.14 x 10^-5)
—20 mm Lead 9.57 x 10^-4 (8.47 x 10^-3) 1.12 x 10^-3 (9.89 x 10^-3) 3.31 x 10^-6 (2.93 x 10^-5)
       
Parallel Drive Inertia 1:1 Reduction 2:1 Reduction  
—5 mm Lead (zero stroke) 4.90 x 10^-3 (4.34 x 10^-2) 2.22 x 10^-3 (1.97 x 10^-2)  
——Add per 25 mm stroke 2.19 x 10^-6 (1.94 x 10^-5) 5.48 x 10^-7 (4.85 x 10^-6)  
—10 mm Lead (zero stroke) 4.91 x 10^-3 (4.34 x 10^-2) 2.23 x 10^-3 (1.97 x 10^-2)  
——Add per 25 mm stroke 2.42 x 10^-6 (2.14 x 10^-5) 6.04 x 10^-7 (5.34 x 10^-6)  
—20 mm Lead (zero stroke) 4.93 x 10^-3 (4.37 x 10^-2) 2.23 x 10^-3 (1.98 x 10^-2)  
——Add per 25 mm stroke 3.31 x 10^-6 (2.93 x 10^-5) 8.28 x 10^-7 (7.33 x 10^-6)
 
FTX125 Performance SpecificationsOpen arrow

FTX125 Specifications

    5 10
Screw Lead mm 5 10
  in 0.197 0.394
Maximum Force* kN 44.5 44.5
  lbf 10,000 10,000
Life at Maximum Force km 249.2 486.3
  in x 10^6 9.81 19.14
C_a (Dynamic Load Rating)* kN 163.7 162.4
  lbf 36,800 36,500
Maximum Input Torque Nm 46.5 82.3
  lbf-in 412 728
Max Rated RPM @ Input Shaft
 
RPM 3,500 3,500
Maximum Linear Speed @ Maximum Rated RPM mm/sec 292 583
  in/sec 11.5 23
Friction Torque Nm 2.23 2.23
  lbf-in 20 20

Intermediate and custom stroke lengths are also available. Belt and pulley inertia varies with ratio and motor selection. Please contact your local sales representative. 
* Maximum allowable actuator-generated force that can be applied routinely. Exceeding this force may result in permanent damage to the actuator. For high force, short stroke applications, consult factory.


 
C_a Derating
FTX125    05 10
*C_a (Dynamic Load Rating) Greater than 900mm Stroke kN 143.4

162.4

lbf 32,240 36,500
 

FTX125 Weights

  kg lb
Base Actuator Weight (Zero Stroke) 21 47
Actuator Weight Adder (Per 25 mm of stroke) 0.84 1.85
Adder for Inline (excluding motor) 6.8 15
Adder for Parallel Drive (excluding motor) 25.6 56.5
Adder for Front Flange 3.6 7.9
Adder for Rear Clevis 6.5 14.3
Adder for Rear Eye 6.3 13.8
Adder for Rear Trunnion 3.1 6.8


 

FTX125 Inertias

Base Unit Inertia Zero Stroke [kg-m^2 (lb-in-s^2)] Add per 25 mm [kg-m^2 (lb-in-s^2)]  
—5 mm Lead 2.55 x 10^-3 (2.26 x 10^-2) 4.62 x 10^-5 (4.09 x 10^-4)  
—10 mm Lead 2.56 x 1^0-3 (2.27 x 10^-2) 4.65 x 10^-5 (4.12 x 10^-4)  
       
Inline Drive Inertia <32 mm Motor Shaft Diameter >32 mm Motor Shaft Diameter Add per 25 mm
—5 mm Lead 2.81 x 10^-3 (2.49 x 10^-2) 3.35 x 10^-3 (2.97 x 10^-2) 4.62 x 10^-5 (4.09 x 10^-4)
—10 mm Lead 2.82 x 10^-3 (2.50 x 10^-2) 3.36 x 10^-3 (2.98 x 10^-2) 4.65 x 10^-5 (4.12 x 10^-4)
       
Parallel Drive Inertia 1:1 Reduction 2:1 Reduction  
—5 mm Lead (zero stroke) 9.43 x 10^-3 (8.34 x 10^-2) 4.66 x 10-3 (4.12 x 10-2)  
——Add per 25 mm stroke 4.62 x 10^-5 (4.09 x 10^-4) 1.15 x 10^-5 (1.02 x 10^-4)  
—10 mm Lead (zero stroke) 9.44 x 10^-3 (8.35 x 10^-2) 4.66 x 10^-3 (4.13 x 10^-2)  
——Add per 25 mm stroke 4.65 x 10^-5 (4.12 x 10^-4) 1.16 x 10^-5 (1.03 x 10^-4)  
FTX160 Performance SpecificationsOpen arrow

FTX160 Specifications

    6 12 30
Screw Lead mm 6 12 30
  in 0.236 0.472 1.181
Maximum Force* kN 89 89 89
  lbf 20,000 20,000 20,000
Life at Maximum Force km 154.9 416.6 358.9
  in x 10^6 6.1 16.4 21.2
C_a (Dynamic Load Rating)* kN 263.7 290.0 233.0
  lbf 59,275 65,200 52,400
Maximum Input Torque Nm 106 212 531
  lbf-in 940 1,880 4,699
Max Rated RPM @ Input Shaft
 
RPM 2,000 2,000 2,000
Maximum Linear Speed @ Maximum Rated RPM mm/sec 201 401 1,000
  in/sec 7.9 15.8 39.0
Friction Torque Nm 4.54 4.54 4.54
  lbf-in 40 40 40

* Maximum allowable actuator-generated force that can be applied routinely. Exceeding this force may result in permanent damage to the actuator. For high force, short stroke applications, consult factory.

 

C_a Derating
FTX160   06 12 30
*C_a (Dynamic Load Rating) Greater than 900mm Stroke kN 223.6 261.2 233
lbf 50,270 58,720 52,400
 

FTX160 Weights

  kg LB
Base Actuator Weight (Zero Stroke) 49 108
Actuator Weight Adder (Per 25 mm of stroke) 1.62 3.6
Adder for Inline (excluding motor) 14.2 31.5
Adder for Parallel Drive (excluding motor) 53.1 117.8
Adder for Front Flange 7.4 16.4
Adder for Rear Clevis 21.2 48.8
Adder for Rear Eye 22.4 49.7
Adder for Rear Trunnion 10.9 24.2
 


FTX160 Inertias

Base Unit Inertia Zero Stroke [kg-m^2 (lbf-in-sec^2)] Add per 25 mm [kg-m^2 (lbf-in-sec^2)]  
6 mm Lead 1.35 x 10^-2 (1.19 x 10^-1) 2.57 x 10^-4 (2.27 x 10^-3)  
12 mm Lead 1.35 x 10^-2 (1.20 x 10^-1) 2.58 x 10^-4 (2.28 x 10^-3)  
30 mm Lead 1.38 x 10^-2 (1.22 x 10^-1) 2.66 x 10^-4 (2.36 x 10^-3)  
Inline Drive Inertia <32 mm Motor Shaft Diameter >32 mm Motor Shaft Diameter Add per 25 mm
6 mm Lead 1.47 x 10^-2 (1.30 x 10^-1) 1.67 x 10^-2 (1.48 x 10^-1) 2.57x 10^-4 (2.27 x 10^-3)
12 mm Lead 1.47 x 10^-2 (1.30 x 10^-1) 1.68 x 10^-2 (1.49 x 10^-1) 2.58 x 10^-4 (2.28 x 10^-3)
30 mm Lead 1.50 x 10^-2 (1.33 x 10^-1) 1.71 x 10^-2 (1.51 x 10^-1) 2.66 x 10^-4 (2.36 x 10^-3)
Parallel Drive Inertia 1:1 Reduction 2:1 Reduction  
—6 mm Lead (zero stroke) 5.27 x 10^-2 (4.67 x 10^-1) 2.30 x 10^-2 (2.04 x 10^-1)  
——Add per 25 mm stroke 2.57 x 10^-4 (2.27 x 10^-3) 6.42 x 10^-5 (5.68 x 10^-4)  
—12 mm Lead (zero stroke) 5.28 x 10^-2 (4.67 x 10^-1) 2.30 x 10^-2 (2.04 x 10^-1)  
——Add per 25 mm stroke 2.58 x 10^-4 (2.28 x 10^-3) 6.45 x 10^-5 (5.71 x 10^-4)  
—30 mm Lead (zero stroke) 5.30 x 10^-2 (4.69 x 10^-1) 2.31 x 10^-2 (2.05 x 10^-1)  
——Add per 25 mm stroke 2.66 x 10^-4 (2.36 x 10^-3) 6.66 x 10^-5 (5.89 x 10^-4)  
FTX215 Performance SpecificationsOpen arrow

FTX215 Specifications

    6 12 30
Screw Lead mm 6 12 30
  in 0.236 0.472 1.181
Maximum Force* kN 177.9 177.9 177.9
  lbf 40,000 40,000 40,000
Life at Maximum Force km 78.7 161.8 414.3
  in x 10^6 3.1 6.4 16.3
C_a (Dynamic Load Rating)* kN 398 423 376
  lbf 89,500 95,200 84,700
Maximum Input Torque Nm 243 425 976
  lbf-in 2,148 3,760 8,642
Max Rated RPM @ Input Shaft
 
RPM 1,750 1,750 1,750
Maximum Linear Speed @ Maximum Rated RPM mm/sec 175 351 875
  in/sec 6.9 13.8 34.4
Friction Torque Nm 5.65 5.65 5.65
  lbf-in 50 50 50

*Maximum allowable actuator-generated force that can be applied routinely. Exceeding this force may result in permanent damage to the actuator. For high force, short stroke applications, consult factory.

 
C_a Derating
FTX215   06 12 30
*C_a (Dynamic Load Rating) Greater than 900mm Stroke kN 359.8 346.7 376
lbf 80,900 77,950 84,700
 


FTX215 Weights

  kg lb
Base Actuator Weight (Zero Stroke) 103 227
Actuator Weight Adder (Per 25 mm of stroke) 2.70 5.96
Adder for Inline (excluding motor) 38.6 85.1
Adder for Parallel Drive (excluding motor) 62.3 137.3
Adder for Front Flange 26.7 58.8
Adder for Rear Clevis 32.5 71.6
Adder for Rear Eye 32.5 71.6
Adder for Rear Trunnion 9.6 212
 


FTX215 Inertias

Base Unit Inertia Zero Stroke [kg-m^2 (lbf-in-sec^2)] Add per 25 mm [kg-m^2 (lbf-in-sec^2)]
  6 mm Lead Add per 25 mm, 6 mm Lead
Base Unit - Input Drive Shaft Only 4.25 x 10^2 (3.76 x 10^1) 8.00 x 10^4 (7.08 x 10^3)
  12 mm Lead Add per 25 mm, 12 mm Lead
Base Unit - Input Drive Shaft Only 4.26 x 10^2 (3.77 x 10^1) 8.02 x 10^4 (7.10 x 10^3)
  30 mm Lead Add per 25 mm, 30 mm Lead
Base Unit - Input Drive Shaft Only 4.31 x 10^2 (3.82 x 10^1) 8.15 x 10^4 (7.21 x 10^3)
     
Inline Drive Inertia 6 mm Lead Add per 25 mm, 6 mm Lead
Inline Unit - w/Motor Coupling 4.43 x 10^2 (3.92 x 10^1) 8.00 x 10^4 (7.08 x 10^3)
Inline Unit - w/Motor Coupling >55mm Shaft Diameter 6.15 x 10^2 (5.44 x 10^1) 8.00 x 10^4 (7.08 x 10^3)
  12 mm Lead Add per 25 mm, 12 mm Lead
Inline Unit - w/Motor Coupling 4.44 x 10^2 (3.93 x 10^1) 8.02 x 10^4 (7.10 x 10^3)
Inline Unit - w/Motor Coupling >55mm Shaft Diameter 6.16 x 10^2 (5.45 x 10^1) 8.02 x 10^4 (7.10 x 10^3)
  30 mm Lead Add per 25 mm, 30 mm Lead
Inline Unit - w/Motor Coupling 4.49 x 10^2 (3.98 x 10^1) 8.15 x 10^4 (7.21 x 10^3)
Inline Unit - w/Motor Coupling >55mm Shaft Diameter 6.21 x 10^2 (5.50 x 10^1) 8.15 x 10^4 (7.21 x 10^3)
     
Parallel Drive Inertia 6 mm Lead Add per 25 mm, 6 mm Lead
1:1 Reduction Parallel Belt Drive 8.73 x 10^2 (7.72 x 10^1) 8.00 x 10^4 (7.08 x 10^3)
2:1 Reduction Parallel Belt Drive 3.14 x 10^2 (2.78 x 10^1) 2.00 x 10^4 (1.77 x 10^3)
  12 mm Lead Add per 25 mm, 12 mm Lead
1:1 Reduction Parallel Belt Drive 8.74 x 10^2 (7.73 x 10^1) 8.02 x 10^4 (7.10 x 10^3)
2:1 Reduction Parallel Belt Drive 3.14 x 10^2 (2.78 x 10^1) 2.01 x 10^4 (1.78 x 10^3)
  30 mm Lead Add per 25 mm, 30 mm Lead
1:1 Reduction Parallel Belt Drive 8.79 x 10^2 (7.78 x 10^1) 8.15 x 10^4 (7.21 x 10^3)

Product Literature

Catalogs, Brochures, and Success Stories

Industrial - Exlar, Brochures/Catalogs
Industrial - Exlar, Brochures/Catalogs
Industrial - Exlar, Brochures/Catalogs
This overview provides a brief summary of new standard products available from Exlar.
Industrial - Exlar, Brochures/Catalogs
Industrial - Exlar, Brochures/Catalogs
Electric Actuation Saves Milk Processor 60% In Power Consumption
Industrial - Exlar, Success Stories
Our newest success story covers: MARKET: Food & Beverage APPLICATION: Butter Press CHALLENGE: Hydraulic oil no longer accepted in application
Industrial - Exlar, Success Stories
Exlar’s roller screw actuator technology was chosen over less capable linear motion solutions.
Industrial - Exlar, Success Stories
The Exlar actuation solution nearly doubled the production rate from 20 cpm to 37 cpm. It also provides significantly better consistency of the finished product.
Show Resources

Actuator Technical Data

Manuals and Technical Tips

Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
A reference of screws (size and pitch) needed for the motor flange codes available with the FTX Series actuators.
Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
Industrial - Exlar, Actuator Technical Tips
Show Resources

Videos

Industrial - Exlar, Product Videos
Our product animation for the FTX Series highlights product features and options available and shows you what makes the FTX an exceptional choice for a variety of industrial applications.
Industrial - Exlar, Product Videos
Exlar® actuators from Curtiss-Wright are an industry leader in electric actuation. Our research, pride, and creativity shine in this short video as we highlight our top product lines.
Industrial - Exlar, Product Videos
Ever wonder about the benefits of changing your system from hydraulic cylinders to electric actuation. We have the information you need.
Industrial - Exlar, Product Videos
Designed and manufactured by Mannetron. Featuring Exlar FT60 Series Actuators.
Show Resources

Find more resources in our InfoCenter

How can we help?

Can you please provide a cost comparison between a ball screw and a roller screw actuator?Arrow
Cost comparison of a roller screw to a ball screw is really a difficult subject, mainly because we have to take into account the differences in the pieces that we are comparing. A roller screw is typically going to be competitive to a ball screw in regards to price because we can oftentimes use a roller screw that is smaller in size compared to its “equivalent” ball screw. This is because of the significant life advantage roller screws have. Therefore, if you are using a smaller frame size roller screw and comparing that to a larger size ball screw, with similar life expectancies, your pricing is going to be very similar. Now depending on what your needs are, if you are looking for something with much greater life, we’re not necessarily comparing an equal product. So you may have to buy two ball screws in comparison to one roller screw. If you look at that from a value standpoint, you may pay more for a similar frame size roller screw but you may have to buy two ball screws in the same period of time that you would have to buy that one roller screw.
How do you calculate the maximum duty cycle allowed vs the amount on current/force applied?Arrow

Below is the maximum-allowable duty cycle for your application given the percentage of input current over the continuous current rating:

For example: If your actuator has a continuous current rating of 10 A and a continuous force rating of 1000 lbf, this means it will take about 10 A to produce 1000 lbf of force, or 5 A to produce 500 lbf of force, and so on. What if you need to push more than 1000 lbf? In most cases, you would look at a stronger stator or a larger actuator. What if it’s only for a few seconds? Could you over-work the current actuator? Well the answer is yes, and calculating by how much isn’t too difficult.

Let’s say you need to push 1500 lbf. This would be equivalent to 1.5x the continuous current rating of 10 A. If you look below, the graph recommends no more than a 22% duty cycle in this case. This means you can run the actuator 22% of the time at 15 A without overheating. The other 78% of the time, it needs to be off/cooling.

How long can you run at peak current?

Not a simple question, nor a simple answer. In reality, so many things affect this (how the system is built and how well the actuator is able to dissipate heat, are there additional heat sinks, particles in the air, degree of vacuum, new starting temp each time? (i.e. doesn’t always start from cold, etc.). Therefore, accurate times and temperature are quite difficult to estimate.

For example: At peak current (2x Continuous), the allowable duty cycle is 4%. That doesn’t mean you can run for 4 hours straight as long as you have 96 hours of off time in between however. From experience, a good rule of thumb we’ve estimated is 30s to a minute of peak current run time. Try to keep it under that, and then of course allow it to cool for the other 96% of the time.

How does a roller screw compare to a hydraulic actuator of equal size and rate force?Arrow
That is going to depend on the application, but with equivalent specifications and characteristics, a roller screw actuator will typically be very similar in size to (sometimes slightly larger than) a comparable hydraulic cylinder. Hydraulics are always going to have their place in the market once you get beyond 100,000 lbs. of force, but anywhere an electromechanical roller screw actuator fits the bill, size will be very similar.
How long until my specific actuator/application needs to be serviced/re-greased?Arrow

We are asked about re-lubrication intervals a lot. The reality is that there is no generic interval to re-lube actuators. It depends on so many things and every application and situation is different, it is nearly impossible to accurately calculate a re-lube interval per application. So instead, we have a rough guideline table (shown below) to give users an idea on when to start checking for old contaminated grease that needs to be replaced. However, since ambient temperature, heat dissipation, speed variation, particles in the air, etc. can vary so much from application to application, this is only a guideline. The actuator should be checked more frequently around the period this table suggests and once it is noticed that the grease is ready to be replaced (Dirty, contaminated / very dark, filled with particles / debris) – a re-lube interval can be determined.

Remember, grease needs to be cleaned out and replaced – don’t just insert more. (Except for FTX’s, those can handle 5-6 greasings before they need to be cleaned out)

RMS ROTATIONAL SPEED (RPM) RECOMMENDED GREASE RENEWAL PERIOD (HOURS)
250 10,000
500 10,000
1000 8000
1500 7000
2000 5800
2500 5000
3000 4000
What are the primary benefits of using an electric actuator system over hydraulics?Arrow
Electric actuators offer high speed and force, are flexible and easily programmable for a variety of load conditions, have high accuracy and repeatability, are efficient, simple to install, require little maintenance, and are environmentally friendly.

By not using a hydraulic system, the user can eliminate oil leaks, reduce pollution, and improve worker safety. Electric actuators are also a non-toxic solution, especially in the food industry
What is the accuracy of the actuator?Arrow

A very common question for us. For the actuator itself, that is easy. There is a mechanical lead accuracy of the screw, which is usually 0.001 in/ft, a typical specification for precision positioning screws of any type. This means that at any point over the cumulative length of the screw, the lead will vary by a maximum of 0.001 inches per foot of screw length. This is not the same as mechanical repeatability. The mechanical repeatability is a tolerance on how close to the same linear position the screw will return, if approaching from the same direction, and driven exactly the same number of turns. This value is approximately 0.0004 inches.

The electronic positioning resolution is a function of the feedback device and the servo amplifier. Let’s assume that we have Exlar’s standard encoder on a GSX30 with 0.2 inches per revolution lead on the roller screw. Exlar’s standard encoder has 2048 lines and 8192 electronic pulses per revolution that it outputs to the servo drive. So in a perfect world, the positioning resolution would be (0.2 in/rev)/ (8192 pulses/rev) or 0.0000244 inches. Anyone who has used servo drives knows that you can’t position to one encoder pulse. Let’s use 10 encoder pulses as a reasonable best positioning capability. This gives us a positioning resolution of 0.000244 inches.

More things to consider: When addressing repeatability and accuracy, several things must also be taken into account. One of these is the stiffness of the system. Stiffness is how much the system will stretch or compress under compressive or tensile forces. If the combination of the stiffness of the actuator and the stiffness of the mechanical system, including all couplings, mounting surface, etc. allows for more compression or stretch than the required positioning resolution of the system, obtaining acceptable positioning results will be nearly impossible. Another consideration is thermal expansion and contraction. Consider a GS actuator attached to a tool that is doing a precision grinding process. Assuming that the tool is steel and 12 inches long, a 5 degree rise in temperature will cause the tool to expand by 0.0006 inches. If the system is programmed to make 0.0002 inch moves, this expansion could cause serious positioning problems. The same applies to the components of the actuator itself. The actuator rod can change in temperature from a cold start up to running temperature. This change may need to be accounted for in very precise positioning applications.

What is the maintenance schedule life for a typical roller screw?Arrow
The maintenance schedule for any geared mechanical device, whether ball screw, roller screw, or gearhead, is going to be based on the amount of heat that is generated in the application, the amount of degradation of the grease, the type of grease being used, and the duty cycle. We provide some guidelines for our customers as starting points, but we recommend that for all new installations the lubrication be periodically inspected for presence and degradation as the best method for determining the right maintenance schedule for a given application. Having said that, we’ve seen repairs of units that have been in use for 15 years and when we’ve asked about grease renewal, they didn’t even realize that the unit could be serviced in the field. So we’ve had situations like that where they’ve gone for long periods of time with effectively no maintenance or no grease renewal. There are other applications that require grease renewal in very short intervals just due to the nature of the application.
What keeps the output shaft from rotating?Arrow
On a conventional roller screw design package, there typically is an anti-rotation groove designed into the housing, and a tab designed into the nut that rides in the housing groove as the actuator extends and retracts. In regards to the inverted roller screw design, part of the installation or the application requirement is going to be having that shaft solidly mounted a machine coupling or tooling on the machine otherwise providing some sort of external anti-rotation device on that output shaft. There are other ways of using splines and different types of non-circular output shafts that can allow for different types of spline nuts that will provide anti-rotation, but typically you’re going to see that mounted on the machine.
How do I estimate life of the actuator?Arrow
The L10 expected life of a roller screw linear actuator is expressed as the linear travel distance that 90% of properly maintained roller screws manufactured are expected to meet or exceed. This calculation should be used for estimation purposes only.

The underlying formula that defines this value is: Travel life in millions of inches, where:
Ca= Dynamic load rating (lbf)
Fcml= Cubic mean applied load (lbf)
ℓ = Roller screw lead (inches)

For additional details on calculating estimated service life, please refer www.cw-actuation.com.

L10=(Ca)3 x ℓ Fcm

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